1. Field of the Invention
The present invention relates to a system for controlling the supercharge pressure in an internal combustion engine having a mechanical supercharger which is connected to the crankshaft of the engine and includes a variable compressing means capable of varying an internal compression ratio.
2. Description of the Prior Art
An internal combustion engine having a mechanical supercharger in which the compression ratio is variable is already known, for example, from Japanese Patent Application Laid-Open No. 221634/90.
However, if the engine is brought into an operational condition in which a high supercharge pressure is introduced, when the variable compressing means for varying the internal compression ratio is out of order due to any cause, so that the compression ratio remains low, the temperature of the intake gas in the engine is increased abnormally due to the high supercharge pressure and a reduction in efficiency of the supercharger and as a result, a knocking in the engine is liable to be produced.